In a 3rd generation partnership project long term evolution (-advanced) (3GPP LTE(-A)) communication system, various channels for an uplink and a downlink are defined in a physical layer used for actual signal transmission. For example, a Physical uplink shared channel (PUSCH), a Physical uplink control channel (PUCCH), a Physical random access channel (PRACH), etc. are defined as uplink physical channels, and a Physical downlink shared channel (PDSCH), a Physical multicast channel (PMCH), a Physical broadcast channel (PBCH), a Physical control format indicator channel (PCFICH), a Physical downlink control channel (PDCCH), a Physical hybrid ARQ indicator channel (PHICH), etc. are defined as downlink physical channels. Hereinafter, “physical” will be omitted from the above channels unless there is any confusion.
The downlink control channel (PDCCH) of the above channels is the channel for transmitting scheduling allocation control information and other control information. In a cellular communication system in which one base station (Node-B) controls a plurality of user equipments (UEs or mobile stations), the several user equipments UEs may receive control information through the PDCCH. At this time, since there is limitation in the number of PDCCHs that may be transmitted from the base station at one time, the base station does not previously allocate different PDCCHs to the respective user equipments UEs but transmits control information to a random user equipment UE through a random PDCCH at respective timing. As a result, the user equipment UE knows that control information transmitted through the PDCCH corresponds to the UE through a user equipment UE identifier included in the PDCCH. At this time, the user equipment UE performs decoding for a plurality of PDCCHs (for a plurality of available PDCCH formats) at respective timing. And, if the user equipment UE determines that the PDCCH corresponds to the user equipment UE, it is operated by receiving the control information.
Meanwhile, although various communication techniques have been developed and implemented, since a size of a control region to which the PDCCH may be transmitted is the same as that of the related art, PDCCH transmission restricts system throughput. Accordingly, in order to prevent system throughput from being restricted by the PDCCH transmission, there has been a discussion that PDCCH transmission should be performed using a PDSCH region of a downlink (DL) subframe. However, since PDCCH transmission based on the PDSCH region enables decoding after one subframe is completely received, a processing time for decoding or demodulation is not sufficient as compared with PDCCH transmission through a control region of a subframe according to the related art.